import { type PokedexEntry, type PokedexEntryDB } from '$lib/models/PokedexEntry';
import { type CatchRecord, type CatchRecordDB } from '$lib/models/CatchRecord';
import { type CombinedData } from '$lib/models/CombinedData';
import type { SupabaseClient } from '@supabase/supabase-js';

// Raw row from game_pokedex_entry_details includes extra ordering columns not in PokedexEntryDB.
type RawDexEntry = PokedexEntryDB & {
	dexNumber: number;
	dexSortOrder: number;
	formSortBucket: number;
	formSortRegionOrder: number;
	formSortRegionalSub: number;
	formSortLabel: string;
	unownSortOrder: number;
};

class CombinedDataRepository {
	private static readonly MAX_ROWS_PER_REQUEST = 1000;

	constructor(
		private supabase: SupabaseClient,
		private userId: string | null,
		private pokedexId: string | null
	) {}

	// Transform Supabase data to match frontend expectations (minimal transformation)
	private transformPokedexEntry(entry: PokedexEntryDB): PokedexEntry {
		return {
			_id: entry.id.toString(),
			pokedexNumber: entry.pokedexNumber,
			pokemon: entry.pokemon,
			form: entry.form || '',
			spriteKey: entry.spriteKey || '',
			canGigantamax: entry.canGigantamax,
			regionToCatchIn: entry.regionToCatchIn || '',
			gamesToCatchIn: entry.gamesToCatchIn || [],
			regionToEvolveIn: entry.regionToEvolveIn || '',
			evolutionInformation: entry.evolutionInformation || '',
			catchInformation: entry.catchInformation || [],
			notes: entry.notes || ''
			// Note: Regional dex numbers are stored in separate regional_dex_numbers table
		};
	}

	private transformCatchRecord(record: CatchRecordDB): CatchRecord {
		return {
			_id: record.id,
			userId: record.userId,
			pokemonId: record.pokemonId.toString(),
			pokedexId: record.pokedexId,
			haveToEvolve: record.haveToEvolve,
			caught: record.caught,
			inHome: record.inHome,
			hasGigantamaxed: record.hasGigantamaxed,
			personalNotes: record.personalNotes
		};
	}

	private buildEntriesQuery(enableForms: boolean, region: string, game: string) {
		let query = this.supabase.from('pokedex_entries').select('*');

		if (!enableForms) {
			// Filter to base forms only. Gendered species (form='male') and Unown ('A') are
			// also flagged isDefaultForm in the pokemon table, so this single check covers them.
			query = query.eq('isDefaultForm', true);
		}

		if (region) {
			query = query.eq('regionToCatchIn', region);
		}

		if (game) {
			query = query.contains('gamesToCatchIn', [game]);
		}

		// Stable ordering from the database: national dex, Unown order, base/female/temporal, then form label.
		query = query
			.order('pokedexNumber', { ascending: true })
			.order('unownSortOrder', { ascending: true })
			.order('formSortBucket', { ascending: true })
			.order('formSortRegionOrder', { ascending: true })
			.order('formSortRegionalSub', { ascending: true })
			.order('formSortLabel', { ascending: true });

		return query;
	}

	private buildDexEntriesQuery(dexScopes: string[], enableForms: boolean, region: string) {
		let query = this.supabase.from('game_pokedex_entry_details').select('*').in('dexId', dexScopes);

		if (!enableForms) {
			// Filter to base forms only. Gendered species (form='male') and Unown ('A') are
			// also flagged isDefaultForm in the pokemon table, so this single check covers them.
			query = query.eq('isDefaultForm', true);
		}

		if (region) {
			query = query.eq('regionToCatchIn', region);
		}

		// Stable ordering: dex order, dex number, Unown order, base/female/temporal, then form label.
		query = query
			.order('dexSortOrder', { ascending: true })
			.order('dexNumber', { ascending: true })
			.order('unownSortOrder', { ascending: true })
			.order('formSortBucket', { ascending: true })
			.order('formSortRegionOrder', { ascending: true })
			.order('formSortRegionalSub', { ascending: true })
			.order('formSortLabel', { ascending: true });

		return query;
	}

	// Fetch all named-form entries for a game from pokedex_entries, excluding already-seen IDs.
	// game_pokedex_entries is seeded from form IS NULL rows, so named forms must be supplemented
	// from here. Deliberately keyed on `form`, NOT isDefaultForm: a default form with a name
	// (e.g. Rotom "Lightbulb") is usually absent from the game dex tables, so filtering on
	// isDefaultForm would drop it from game-scoped form dexes entirely. excludeIds already
	// dedupes anything the dex table does list.
	private async fetchFormsForGame(
		game: string,
		region: string,
		excludeIds: Set<number>
	): Promise<PokedexEntryDB[]> {
		const allForms: PokedexEntryDB[] = [];
		let start = 0;
		const maxRows = CombinedDataRepository.MAX_ROWS_PER_REQUEST;

		for (;;) {
			const end = start + maxRows - 1;
			let query = this.supabase.from('pokedex_entries').select('*').not('form', 'is', null);

			if (game) {
				query = query.contains('gamesToCatchIn', [game]);
			}
			if (region) {
				query = query.eq('regionToCatchIn', region);
			}

			const { data, error } = await query.order('id', { ascending: true }).range(start, end);

			if (error) {
				console.error('Error fetching forms for game:', error);
				return [];
			}

			if (!data || data.length === 0) break;

			allForms.push(...(data as PokedexEntryDB[]).filter((e) => !excludeIds.has(e.id)));

			if (data.length < maxRows) break;
			start = end + 1;
		}

		return allForms;
	}

	private async fetchAllDexEntries(
		dexScopes: string[],
		enableForms: boolean,
		region: string,
		game: string = ''
	): Promise<PokedexEntryDB[]> {
		if (dexScopes.length === 0) return [];

		const entries: RawDexEntry[] = [];
		let start = 0;
		const maxRows = CombinedDataRepository.MAX_ROWS_PER_REQUEST;

		for (;;) {
			const end = start + maxRows - 1;
			const { data, error } = await this.buildDexEntriesQuery(dexScopes, enableForms, region).range(
				start,
				end
			);

			if (error) {
				console.error('Error finding dex-scoped combined data:', error);
				return [];
			}

			if (!data || data.length === 0) {
				break;
			}

			entries.push(...(data as RawDexEntry[]));

			if (data.length < maxRows) {
				break;
			}

			start = end + 1;
		}

		// When forms are enabled, game_pokedex_entries only has base forms, so supplement from pokedex_entries.
		if (!enableForms || !game) {
			return entries as PokedexEntryDB[];
		}

		// Build lookup: pokedexNumber → dex position (from the raw game dex data)
		const dexInfoByPokedexNumber = new Map<number, { dexNumber: number; dexSortOrder: number }>();
		for (const entry of entries) {
			if (!dexInfoByPokedexNumber.has(entry.pokedexNumber)) {
				dexInfoByPokedexNumber.set(entry.pokedexNumber, {
					dexNumber: entry.dexNumber ?? 0,
					dexSortOrder: entry.dexSortOrder ?? 0
				});
			}
		}

		// Fetch forms not already covered by game_pokedex_entries
		const existingIds = new Set(entries.map((e) => e.id));
		const formEntries = await this.fetchFormsForGame(game, region, existingIds);

		if (formEntries.length === 0) {
			return entries as PokedexEntryDB[];
		}

		// Merge and sort: dex entries first (they are the canonical base form for the regional dex),
		// then supplemented forms. Within each group, sort by form fields.
		type TaggedEntry = RawDexEntry & { _isDexEntry: boolean };
		const merged: TaggedEntry[] = [
			...entries.map((e) => ({ ...e, _isDexEntry: true })),
			...(formEntries as RawDexEntry[]).map((e) => ({ ...e, _isDexEntry: false }))
		];

		merged.sort((a, b) => {
			const aDex = dexInfoByPokedexNumber.get(a.pokedexNumber) ?? {
				dexNumber: 9999,
				dexSortOrder: 9999
			};
			const bDex = dexInfoByPokedexNumber.get(b.pokedexNumber) ?? {
				dexNumber: 9999,
				dexSortOrder: 9999
			};
			if (aDex.dexSortOrder !== bDex.dexSortOrder) return aDex.dexSortOrder - bDex.dexSortOrder;
			if (aDex.dexNumber !== bDex.dexNumber) return aDex.dexNumber - bDex.dexNumber;
			if ((a.unownSortOrder ?? 0) !== (b.unownSortOrder ?? 0))
				return (a.unownSortOrder ?? 0) - (b.unownSortOrder ?? 0);
			// Dex entries (canonical regional base form) sort before supplemented forms.
			if (a._isDexEntry !== b._isDexEntry) return a._isDexEntry ? -1 : 1;
			if ((a.formSortBucket ?? 0) !== (b.formSortBucket ?? 0))
				return (a.formSortBucket ?? 0) - (b.formSortBucket ?? 0);
			if ((a.formSortRegionOrder ?? 0) !== (b.formSortRegionOrder ?? 0))
				return (a.formSortRegionOrder ?? 0) - (b.formSortRegionOrder ?? 0);
			if ((a.formSortRegionalSub ?? 0) !== (b.formSortRegionalSub ?? 0))
				return (a.formSortRegionalSub ?? 0) - (b.formSortRegionalSub ?? 0);
			return (a.formSortLabel ?? '').localeCompare(b.formSortLabel ?? '');
		});

		return merged as PokedexEntryDB[];
	}

	private dedupeEntries(entries: PokedexEntryDB[]): PokedexEntryDB[] {
		const seen = new Set<number>();
		const deduped: PokedexEntryDB[] = [];

		for (const entry of entries) {
			if (seen.has(entry.id)) continue;
			seen.add(entry.id);
			deduped.push(entry);
		}

		return deduped;
	}

	private async fetchEntriesByRange(
		from: number,
		to: number,
		enableForms: boolean,
		region: string,
		game: string
	): Promise<PokedexEntryDB[]> {
		const entries: PokedexEntryDB[] = [];
		let start = from;
		const maxRows = CombinedDataRepository.MAX_ROWS_PER_REQUEST;

		while (start <= to) {
			const end = Math.min(to, start + maxRows - 1);
			const { data, error } = await this.buildEntriesQuery(enableForms, region, game).range(
				start,
				end
			);

			if (error) {
				console.error('Error finding paginated combined data:', error);
				return [];
			}

			if (!data || data.length === 0) {
				break;
			}

			entries.push(...data);

			if (data.length < end - start + 1) {
				break;
			}

			start = end + 1;
		}

		return entries;
	}

	private async fetchAllEntries(
		enableForms: boolean,
		region: string,
		game: string
	): Promise<PokedexEntryDB[]> {
		const entries: PokedexEntryDB[] = [];
		let start = 0;
		const maxRows = CombinedDataRepository.MAX_ROWS_PER_REQUEST;

		for (;;) {
			const end = start + maxRows - 1;
			const { data, error } = await this.buildEntriesQuery(enableForms, region, game).range(
				start,
				end
			);

			if (error) {
				console.error('Error finding combined data:', error);
				return [];
			}

			if (!data || data.length === 0) {
				break;
			}

			entries.push(...data);

			if (data.length < maxRows) {
				break;
			}

			start = end + 1;
		}

		return entries;
	}

	private async fetchCatchRecords(entryIds: number[], userId: string): Promise<CatchRecordDB[]> {
		if (!this.pokedexId) return [];
		if (entryIds.length === 0) return [];

		const records: CatchRecordDB[] = [];
		const chunkSize = 1000;

		for (let i = 0; i < entryIds.length; i += chunkSize) {
			const chunk = entryIds.slice(i, i + chunkSize);
			const { data, error } = await this.supabase
				.from('catch_records')
				.select('*')
				.eq('userId', userId)
				.eq('pokedexId', this.pokedexId)
				.in('pokemonId', chunk);

			if (error) {
				console.error('Error loading catch records:', error);
				continue;
			}

			if (data) {
				records.push(...data);
			}
		}

		return records;
	}

	async findAllCombinedData(
		userId: string,
		enableForms: boolean = true,
		region: string = '',
		game: string = '',
		dexScopes: string[] = []
	): Promise<CombinedData[]> {
		const entries =
			dexScopes.length > 0
				? this.dedupeEntries(await this.fetchAllDexEntries(dexScopes, enableForms, region, game))
				: await this.fetchAllEntries(enableForms, region, game);

		if (!entries || entries.length === 0) {
			return [];
		}

		// Get catch records for all entries
		let catchRecords: CatchRecordDB[] = [];
		if (userId && this.pokedexId) {
			const entryIds = entries.map((entry) => entry.id);
			catchRecords = await this.fetchCatchRecords(entryIds, userId);
		}

		// Combine the data exactly like master branch
		const combinedData = entries.map((entry) => {
			const userCatchRecord = catchRecords.find((record) => record.pokemonId === entry.id) || null;

			const transformedEntry = this.transformPokedexEntry(entry);
			const transformedCatchRecord = userCatchRecord
				? this.transformCatchRecord(userCatchRecord)
				: null;

			return {
				pokedexEntry: transformedEntry,
				catchRecord: transformedCatchRecord
			};
		});

		// Box placement is calculated dynamically on the frontend based on the current sort order.
		return combinedData;
	}

	async findCombinedData(
		userId: string,
		page: number = 1,
		limit: number = 20,
		enableForms: boolean = true,
		region: string = '',
		game: string = '',
		dexScopes: string[] = []
	): Promise<CombinedData[]> {
		const from = (page - 1) * limit;
		const to = from + limit - 1;
		const entries =
			dexScopes.length > 0
				? this.dedupeEntries(
						await this.fetchAllDexEntries(dexScopes, enableForms, region, game)
					).slice(from, to + 1)
				: await this.fetchEntriesByRange(from, to, enableForms, region, game);

		if (!entries || entries.length === 0) {
			return [];
		}

		// Get catch records for these entries
		let catchRecords: CatchRecordDB[] = [];
		if (userId && this.pokedexId) {
			const entryIds = entries.map((entry) => entry.id);
			catchRecords = await this.fetchCatchRecords(entryIds, userId);
		}

		// Combine the data exactly like master branch
		const combinedData = entries.map((entry) => {
			const userCatchRecord = catchRecords.find((record) => record.pokemonId === entry.id) || null;

			const transformedEntry = this.transformPokedexEntry(entry);
			const transformedCatchRecord = userCatchRecord
				? this.transformCatchRecord(userCatchRecord)
				: null;

			return {
				pokedexEntry: transformedEntry,
				catchRecord: transformedCatchRecord
			};
		});

		// Box placement is calculated dynamically on the frontend based on the current sort order.
		return combinedData;
	}

	async countCombinedData(
		enableForms: boolean,
		region: string,
		game: string,
		dexScopes: string[] = []
	): Promise<number> {
		if (dexScopes.length > 0) {
			const entries = this.dedupeEntries(
				await this.fetchAllDexEntries(dexScopes, enableForms, region, game)
			);
			return entries.length;
		}

		let query = this.supabase.from('pokedex_entries').select('id', { count: 'exact', head: true });

		// Apply same filters as in findCombinedData
		if (!enableForms) {
			// Filter to base forms only. Gendered species (form='male') and Unown ('A') are
			// also flagged isDefaultForm in the pokemon table, so this single check covers them.
			query = query.eq('isDefaultForm', true);
		}

		if (region) {
			query = query.eq('regionToCatchIn', region);
		}

		if (game) {
			query = query.contains('gamesToCatchIn', [game]);
		}

		const { count, error } = await query;

		if (error) {
			console.error('Error counting combined data:', error);
			return 0;
		}

		return count || 0;
	}
}

export default CombinedDataRepository;